1. Field of the Invention
The present invention relates to a display apparatus, and more particularly to a display apparatus of an eyeglass type, a goggle type, or a helmet type as so called as a head mounted display, which is arranged to be mounted on the head of an information viewer (observer) and to guide image information displayed on a display means to the eyes of the information viewer, thereby letting the information viewer observe the image information.
2. Related Background Art
There have been proposed heretofore a variety of display apparatus which are arranged to be mounted on the head of information viewer and let the information viewer observe image information displayed on the display means. For example, such display apparatus were proposed in Japanese Laid-open Patent Applications No. 3-113412 and No. 3-113413. Besides, Japanese Laid-open Patent Application No. 59-117876 suggests a personal type display apparatus using a transmission type liquid crystal display as the display means. This application discloses a two-piece example of a goggle-type holding means and the main body and an all-in-one example of a cap-shape holding means in which all elements are built.
Since the display apparatus as a head mounted display is personally used as mounted on the head of information viewer, it is desirable that a portable power supply not requiring a power supply cord be used or that the entire apparatus be arranged as to be light in weight. Generally, decreasing the weight of the power supply results in decreasing the capacity of a battery.
The display apparatus using the personal type liquid crystal display had such a problem that if the apparatus was in a non-use state though the information viewer set the display apparatus on, for example when the viewer fell into a doze or when the viewer took off the display apparatus from the head, a power on state was maintained though the display apparatus was not viewed, thus wasting the power.